chore: import upstream snapshot with attribution

cli-tool/components/skills/git/git-context-controller/references/file_formats.md

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+# GCC File Format Reference
+
+## main.md
+
+The global roadmap. Updated on every MERGE and periodically on significant COMMITs.
+
+```markdown
+# Project Roadmap
+
+## Objectives
+- [ ] Objective 1
+- [x] Objective 2 (completed)
+
+## Milestones
+### M1: Feature X implemented
+- Branch: feature-x
+- Commits: 3
+- Status: merged
+
+### M2: Bug fix Y
+- Branch: fix-y
+- Commits: 1
+- Status: active
+
+## Active Branches
+- `experiment-z`: Testing alternative approach for caching
+```
+
+## commit.md
+
+Each commit entry captures the full reasoning context, not just a diff summary.
+
+```markdown
+## [C003] Implement retry logic for API calls
+- **Date**: 2025-01-15T10:30:00Z
+- **Branch**: feature-resilience
+- **Branch Purpose**: Add fault tolerance to external API integrations
+- **Previous Progress**: Identified failure patterns in logs; designed retry strategy with exponential backoff
+- **This Commit's Contribution**: Implemented `retry_with_backoff(fn, max_retries=3)` in `utils/http.py`. Added unit tests covering timeout, 5xx, and network error scenarios. Validated against staging API.
+- **Files touched**: utils/http.py, tests/test_http.py
+```
+
+## log.md
+
+Fine-grained OTA (Observation-Thought-Action) trace entries. Keep the last 50 entries maximum.
+
+```markdown
+---
+**[OTA-042]** 2025-01-15T10:15:00Z | Branch: feature-resilience
+- **Observation**: API calls to /users endpoint failing with 503 errors intermittently
+- **Thought**: Need exponential backoff rather than fixed delay; should cap at 3 retries to avoid infinite loops
+- **Action**: Implementing retry_with_backoff() in utils/http.py
+
+---
+**[OTA-043]** 2025-01-15T10:28:00Z | Branch: feature-resilience
+- **Observation**: Tests passing for timeout and 5xx scenarios
+- **Thought**: Ready to commit this milestone - retry logic is complete and validated
+- **Action**: COMMIT with summary of retry implementation
+```
+
+## metadata.yaml
+
+Structured infrastructure state. Updated on every operation.
+
+```yaml
+version: 1
+created: "2025-01-10T08:00:00Z"
+proactive_commits: true
+branches:
+  - name: main
+    status: active
+    created: "2025-01-10T08:00:00Z"
+  - name: feature-resilience
+    status: active
+    created: "2025-01-15T09:00:00Z"
+    parent: main
+  - name: experiment-cache
+    status: abandoned
+    created: "2025-01-12T14:00:00Z"
+    reason: "Redis dependency too heavy for this use case"
+file_tree:
+  - src/main.py
+  - src/utils/http.py
+  - tests/test_http.py
+dependencies:
+  - requests>=2.28
+  - pytest>=7.0
+config:
+  language: python
+  framework: fastapi
+```
+
+## Branch Directory Structure
+
+Each branch under `.GCC/branches/<branch-name>/` contains:
+
+```
+.GCC/branches/feature-resilience/
+├── commit.md    # Commits specific to this branch
+├── log.md       # OTA traces for this branch
+└── summary.md   # Branch purpose and current status
+```
+
+### summary.md (per-branch)
+
+```markdown
+# Branch: feature-resilience
+
+## Purpose
+Add fault tolerance to external API integrations to handle intermittent 503 errors.
+
+## Status: active
+## Parent: main
+## Created: 2025-01-15T09:00:00Z
+
+## Key Decisions
+- Using exponential backoff (not fixed delay)
+- Max 3 retries to prevent cascade failures
+- Logging all retry attempts for observability
+```