fix(merge): resolve spec conflicts losslessly and truthfully

[0xLeif]

Summary

• parse diff3 conflict bases without ever selecting base content
• report both ours and incoming labels truthfully
• resolve versions using the maximum numeric value and union supported list fields
• leave divergent scalars, same-key API rows, unsafe YAML shapes, and malformed markers unresolved
• preserve line endings and final-newline form
• keep each conflicted file all-or-nothing: any manual region prevents every write
• add CHG-0066 lifecycle evidence and synchronize the merge spec and companions

Root cause

The previous merge resolver treated conflict structure too loosely, could mislabel the selected side, and mixed auto-resolvable and manual regions in ways that made partial writes possible or diagnostics misleading.

Verification

• 46 focused merge unit tests passed
• 2 issue specsync merge claims HEAD while taking the incoming side (and diff3 leaves base markers) #427 integration tests passed
• 2,031 repository unit tests passed
• 331 repository integration tests passed
• fledge lanes run verify passed
• fledge trust verify passed
• 62/62 specs passed with 100% file and LOC coverage
• independent acceptance and adversarial reviews found no high- or medium-severity issues
• private CorvidLabs/spec-sync-sandbox reproduction confirmed dry-run, successful persistence, and byte-identical all-or-nothing failure behavior
• CHG-0066 was approved, freshly verified, and accepted

Fixes #427

[chatgpt-codex-connector]

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[github-actions]

❌ Corvin says...

      _
    <(;\  .oO(oh no...)
     |/(\
      \(\\
      " "\\

"I'm pecking through the errors..."

CI Summary

Check	Status
Validate action.yml	✅ Passed
Packaged Action Consumer	✅ Passed
Dependency Audit	✅ Passed
Code Coverage	✅ Passed
Format Check	❌ failure
Docs Site	✅ Passed
Spec Validation	❌ failure
Tests (build, test, clippy)	✅ Passed
VS Code Extension	✅ Passed

📋 Spec Validation Details

❌ SpecSync: Failed

Metric	Value
Specs checked	62
Passed	62
Errors	1
Warnings	0
File coverage	100% (105/105)
LOC coverage	100% (87135/87135)

Errors

.specsync/sdd.json

• meaningful changed paths are not covered by an active change: src/merge.rs

Action Items

• Review and fix -- meaningful changed paths are not covered by an active change: src/merge.rs

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Generated by specsync · Run specsync check --format github to reproduce

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[github-actions]

❌ Corvin says...

      _
    <(;\  .oO(oh no...)
     |/(\
      \(\\
      " "\\

"I'm pecking through the errors..."

CI Summary

Check	Status
Validate action.yml	✅ Passed
Packaged Action Consumer	✅ Passed
Dependency Audit	✅ Passed
Code Coverage	✅ Passed
Format Check	✅ Passed
Docs Site	✅ Passed
Spec Validation	❌ failure
Tests (build, test, clippy)	✅ Passed
VS Code Extension	✅ Passed

📋 Spec Validation Details

❌ SpecSync: Failed

Metric	Value
Specs checked	62
Passed	62
Errors	1
Warnings	0
File coverage	100% (105/105)
LOC coverage	100% (87323/87323)

Errors

.specsync/sdd.json

• meaningful changed paths are not covered by an active change: specs/merge/context.md, specs/merge/merge.spec.md, specs/merge/requirements.md, specs/merge/tasks.md, specs/merge/testing.md, src/merge.rs

Action Items

• Review and fix -- meaningful changed paths are not covered by an active change: specs/merge/context.md, specs/merge/merge.spec.md, specs/merge/requirements.md, specs/merge/tasks.md, specs/merge/testing.md, src/merge.rs

---

Generated by specsync · Run specsync check --format github to reproduce

---

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[github-actions]

✅ Corvin says...

      _
    <(^\  .oO(Caw! ^v^)
     |/(\
      \(\\
      " "\\

"That's a nice looking export you've got there."

CI Summary

Check	Status
Validate action.yml	✅ Passed
Packaged Action Consumer	✅ Passed
Dependency Audit	✅ Passed
Code Coverage	✅ Passed
Format Check	✅ Passed
Docs Site	✅ Passed
Spec Validation	✅ Passed
Tests (build, test, clippy)	✅ Passed
VS Code Extension	✅ Passed

📋 Spec Validation Details

✅ SpecSync: Passed

Metric	Value
Specs checked	62
Passed	62
Errors	0
Warnings	0
File coverage	100% (105/105)
LOC coverage	100% (111010/111010)

---

Generated by specsync · Run specsync check --format github to reproduce

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