refactor(source-control): GitManager reads provider resolvers, not host kinds

[juliusmarminge]

The first cleanup layer. GitManager checked provider.kind === "github" or "forgejo" in four places, so host behavior lived in generic server code. Each check is now a resolver on SourceControlProvider that the host's own package implements. Generic code asks the provider a question; it doesn't test a flag that only one host would ever set.

Resolver	Implemented by	Replaces
headBranchProbe({ headSelectors, state }) → { headSelectors, limit }	GitHub drops owner:branch selectors and reads 100	kind === "github" ? 100 : 1/20 plus the GitHub-only selector filter. Hosts without it ask about every selector, reading 1 (open) or 20 (any state).
readChangeRequestTemplate({ cwd, treeish })	GitHub's .github/pull_request_template.md convention	followChangeRequestTemplates && kind === "github"
repositoryNameFromRemoteUrl(url)	Forgejo strips an installation mount from HTTP paths	providerKind === "forgejo"

Supporting changes:

• PR template detection moves into the GitHub package. apps/server/src/sourceControl/PrTemplateDetection.ts becomes @t3tools/source-control-github/server/gitHubChangeRequestTemplate and reads through the host's git. SourceControlHost.git.execute now accepts the output limits it needs. Its test stays in the server, because it runs real git.
• GitHub's reasoning moves with its values. The comments explaining GitHub's probe values now sit in the GitHub package.
• The remote-path parse moves to core as repositoryPathFromRemoteUrl.
• bindProviderContext spreads the provider, so new resolvers pass through without editing it.
• One moved test now follows the Effect conventions. The Forgejo review test came over in refactor(source-control): Forgejo lives in @t3tools/source-control-forgejo #17581 unchanged from main. It faked HTTP with an async fetch behind FetchHttpClient and read request bodies with JSON.parse. It now uses HttpClient.make(...) and decodes through Schema, with the same assertions.

Behavior is unchanged: every host keeps the values it had. Existing tests already pin GitHub's --limit 100, the selector filter, template following, and Forgejo's mounted paths. They pass, and the only edits are to fixtures.

Verified:

• tsc across apps/server and five packages
• knip
• a frozen-lockfile install
• the tests for the whole open stack: 52 files, 1211 tests
• the Effect-shortcut grep finds no hits in this layer's added lines

🤖 Generated with Claude Code — Claude Opus 5.5 in T3 Code

[macroscopeapp]

Approvability

Verdict: Approved at 3fd41c7

Macroscope's review found this PR approvable — This is a contained source-control refactor that moves existing GitHub and Forgejo behavior behind provider capabilities without changing product defaults or introducing new workflows. Updated tests cover the relocated template handling and provider-specific URL behavior.

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📥 Commits

Reviewing files that changed from the base of the PR and between 604a15a and 3fd41c7.

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📒 Files selected for processing (8)

• apps/server/src/git/GitManager.test.ts
• apps/server/src/git/GitManager.ts
• apps/server/src/sourceControl/gitHubChangeRequestTemplate.test.ts
• packages/source-control-core/src/server/SourceControlHost.ts
• packages/source-control-core/src/server/SourceControlProvider.ts
• packages/source-control-github/package.json
• packages/source-control-github/src/server/GitHubSourceControlProvider.ts
• packages/source-control-github/src/server/gitHubChangeRequestTemplate.ts

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📝 Walkthrough

Walkthrough

Source-control providers now expose optional capabilities for repository parsing and change-request behavior. GitManager uses provider services to resolve repository names, select head-branch probes, set result limits, and read templates. Forgejo and GitHub provide provider-specific implementations.

Changes

Provider capabilities and GitManager integration

Layer / File(s)	Summary
Provider capability contracts packages/source-control-core/src/server/SourceControlProvider.ts, packages/source-control-core/src/server/SourceControlHost.ts	The provider contract adds shared remote-URL path parsing and optional capabilities for repository names, head-branch probes, and template reading. The Git execution input adds output-size and truncation-marker options.
Provider-specific capabilities packages/source-control-forgejo/src/server/ForgejoSourceControlProvider.ts, packages/source-control-forgejo/src/server/ForgejoSourceControlProvider.test.ts, packages/source-control-github/src/server/GitHubSourceControlProvider.ts, packages/source-control-github/src/server/gitHubChangeRequestTemplate.ts, packages/source-control-github/package.json, apps/server/src/sourceControl/gitHubChangeRequestTemplate.test.ts	Forgejo registers repository-name parsing, and its review-submission test uses an HttpClient mock. GitHub provides head-branch probe settings and template reading. The GitHub template detector is exported as detect through the package export.
GitManager uses provider capabilities apps/server/src/sourceControl/SourceControlProviderRegistry.ts, apps/server/src/git/GitManager.ts, apps/server/src/git/GitManager.test.ts	The registry preserves provider service properties. GitManager uses provider services for repository parsing, selector selection, result limits, and template reading. GitManager tests configure provider capabilities and template reading.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Refactor

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Merge Risk: ⚪ Minimal · up to 3fd41

The provider-capability change is mergeable after normal checks; no material behavior regression was established.

Pre-merge checks | 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title clearly and concisely describes the main refactor: GitManager now uses provider resolvers instead of host-kind checks.
Description check		The description clearly explains the problem, implementation changes, affected capabilities, compatibility behavior, and verification results. It does not provide a separate scope-and-approval referen…

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	5.0 KiB	5.0 KiB	0 B (0.0%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	20.9 KiB	20.9 KiB	0 B (0.0%)	29.3 KiB	✅
Codex	Live turn messages	2	2	0 (0.0%)	8	✅
Claude	Total thread wire	5.0 KiB	5.0 KiB	+24 B (+0.5%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.2 KiB	+24 B (+2.0%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	21.2 KiB	21.2 KiB	+41 B (+0.2%)	29.3 KiB	✅
Claude	Live turn messages	1	2	+1 (+100.0%)	8	✅

Baseline: c85dc64 · PR result: 3fd41c7 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

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