Add bounded structured dependency-source analysis

[Spectorian]

Summary

• Stack on feat(sc10): detect direct dependency-source redirection #430 to replace its executable-surface coverage notices with bounded, syntax-aware analysis.
• Parse supported shell units with exact-pinned Tree-sitter Bash, a bounded callable reader, conservative literal state, and localized limitations for unsupported or ambiguous semantics.
• Add typed dependency-source command adapters for npm, Yarn, pnpm, pip, Poetry, Cargo, uv, and literal bundle-local Maven settings references.
• Analyze structurally proven heredoc/here-string generated configurations, then converge direct and executable evidence through atomic finding and ledger accounting.
• Complete the committed SC10 corpus as explicit finding, inert, or truthful limitation outcomes.

Stack

This draft targets codex/sc10-core-config-coverage and depends on #430. It should remain stacked until the base change is integrated.

Security and product boundary

• Deterministic, local-only, static-only, advisory HIGH evidence.
• No command execution, network/DNS/reputation calls, telemetry, trust lists, recommendation-policy change, raw-text fallback parser, general shell interpreter, or general file-descriptor model.
• Provider output may add presentation context but cannot suppress, downgrade, rewrite, or otherwise mutate deterministic SC10 results.
• Sensitive values are removed from findings, evidence, provider requests, logs, and terminal/JSON/Markdown/SARIF output.

Parser and deployment impact

• Adds required exact pins: tree-sitter==0.25.2 and tree-sitter-bash==0.25.1.
• CI verifies the source distribution, wheel, Docker smoke path, and the wheel-only Python/platform matrix.
• Parser import, ABI, deadline, syntax, and resource failures are represented as bounded failed/partial/skipped work rather than silent clean coverage.

Explicit limitations

Unsupported descriptors, downstream pipeline writers, data-to-shell pipelines, xargs, env -S, ambiguous wrapper options, dynamic structure-changing expansion, and unproven generated-file writes fail closed as localized incomplete coverage. Dockerfile RUN, Make recipes, unsupported shell dialects, indented Markdown code, and shell fences outside supported README/SKILL Markdown remain explicit unscanned executable coverage.

Verification

• uv sync --all-extras --frozen
• Focused SC10 suites: 1,077 passed, 3 expected xfails
• CI workflow contract: 4 passed
• make test-ci: 4,169 passed, 13 skipped, 38 deselected, 7 expected xfails; 88% coverage
• Ruff lint and format checks
• Source distribution and wheel build
• Public-copy scrub across the complete candidate diff, commit subjects, fixtures, docs, and this PR text