fix: use indexed commit in generated editor files - #1875

Symbols changed (blast radius)

• tests/unit/generation/test_editor_file_fetcher.py::test_fetch_indexed_commit_uses_commit_stored_with_index: added, 0 caller(s) outside this PR
• packages/core/src/repowise/core/generation/editor_files/fetcher.py::EditorFileDataFetcher: body, 5 caller(s) outside this PR: packages/cli/src/repowise/cli/commands/claude_md_cmd.py::_generate, packages/cli/src/repowise/cli/editor_files.py::fetch_editor_file_data, packages/cli/src/repowise/cli/editor_integrations/claude.py::_write_claude_md_async, packages/server/src/repowise/server/routers/claude_md.py::generate_claude_md, packages/server/src/repowise/server/routers/claude_md.py::get_claude_md
• packages/core/src/repowise/core/generation/editor_files/fetcher.py::fetch: body, 5 caller(s) outside this PR: packages/cli/src/repowise/cli/commands/claude_md_cmd.py::_generate, packages/cli/src/repowise/cli/editor_files.py::fetch_editor_file_data, packages/cli/src/repowise/cli/editor_integrations/claude.py::_write_claude_md_async, packages/server/src/repowise/server/routers/claude_md.py::generate_claude_md, packages/server/src/repowise/server/routers/claude_md.py::get_claude_md

Review priority (recent bug-fix history)

• packages/core/src/repowise/core/generation/editor_files/fetcher.py: fixed 5x in the last ~6 months
• tests/unit/generation/test_editor_file_fetcher.py: fixed 3x in the last ~6 months

Touched hotspots (blast radius)

• packages/core/src/repowise/core/generation/editor_files/fetcher.py: 12 commits/90d, 4 dependents, owner Raghav Chamadiya
• tests/unit/generation/test_editor_file_fetcher.py: 3 commits/90d, 0 dependents, owner Raghav Chamadiya

Hidden coupling (co-change partners not in this PR)

• packages/core/src/repowise/core/generation/editor_files/fetcher.py co-changes with packages/core/src/repowise/core/generation/templates/claude_md.j2 (7x)
• packages/core/src/repowise/core/generation/editor_files/fetcher.py co-changes with packages/core/src/repowise/core/generation/editor_files/data.py (7x)
• packages/core/src/repowise/core/generation/editor_files/fetcher.py co-changes with packages/server/src/repowise/server/mcp_server/tool_overview.py (5x)
• packages/core/src/repowise/core/generation/editor_files/fetcher.py co-changes with tests/unit/generation/test_editor_file_base.py (5x)
• packages/core/src/repowise/core/generation/editor_files/fetcher.py co-changes with packages/server/src/repowise/server/mcp_server/tool_health.py (4x)

Change risk

• Raw change-risk score: 3.9/10 (banded low, riskier than 8% of this repo's commits)