Validate pipeline specs during submit

[Volv-G]

Summary

Run the full local pipeline authoring validator during tangle sdk pipeline-runs submit and --dry-run, and route the high-level runner path through the same default validation hook. This catches authoring-shape errors locally with Pipeline validation failed before a pipeline run is created.

Also bumps tangle-cli from 0.1.2 to 0.1.3.

What changed

• Added collect_pipeline_spec_errors(...) alongside validate_pipeline_spec(...) so submit/run flows can compose with the existing list[str] validation hook contract.
• Moved the OSS default validate_pipeline_for_run(...) implementation to the base PipelineRunHooks, so the real PipelineRunManager submit path and PipelineRunner inheritance path share the same behavior.
• Validates in the PipelineRunManager.prepare_submit_payload_from_spec(...) choke point, which backs both:
  • tangle sdk pipeline-runs submit
  • tangle sdk pipeline-runs submit --dry-run
• Validation timing is post-hydration for normal submit, so the hydrated/resolved pipeline graph is validated. With --no-hydrate, the as-is local spec is validated.
• Root pipeline shape is enforced by the authoring validator itself: the root must have implementation.graph; a bare implementation.container root fails with implementation.graph must be an object.
• Updated README docs and tests for submit/dry-run validation, bare-container root rejection, post-hydration valid/invalid template cases, and runner skip-validation plumbing.

Relationship to PR #27

This is independent of PR #27 and is based on master, not on PR #27. It intentionally does not include PR #27’s proposed --skip-validation CLI flag or separate narrow submit-root check. Instead, submit uses the existing full pipelines validate authoring validator at the manager choke point.

Test plan

• uv run --frozen tangle version → 0.1.3
• uv run --frozen pytest -q → 692 passed, 4 warnings
• uv run --frozen ruff check packages/tangle-cli/src/tangle_cli/__init__.py packages/tangle-cli/src/tangle_cli/pipeline_run_manager.py packages/tangle-cli/src/tangle_cli/pipeline_runner.py packages/tangle-cli/src/tangle_cli/pipelines.py tests/test_pipeline_runs_cli.py tests/test_pipelines_cli.py tests/test_packaging.py → passed
• git diff --check → passed