[stage1] fix: strip YAML frontmatter from TOML integration prompts

[RbBtSn0w]

Summary

Fix the active TOML integration path used by specify init --ai gemini/tabnine.

This PR corrects two problems in TomlIntegration:

• YAML description values were not parsed with real YAML semantics, so block scalar descriptions (| / >) were mishandled
• generated TOML prompt content incorrectly included the source Markdown template frontmatter instead of just the command body

What changed

• parse TOML integration descriptions from YAML frontmatter instead of line-scanning description:
• preserve YAML block scalar semantics for multiline descriptions
• split processed templates into frontmatter and body before rendering TOML, so prompt contains only the command body
• add regression coverage for block scalar descriptions and prompt output excluding YAML frontmatter

Validation

• uv run --with pytest python -m pytest tests/integrations/test_integration_gemini.py tests/integrations/test_integration_tabnine.py -q
• uv run --with pytest python -m pytest tests/integrations -q
• real output check via specify init --ai gemini --offline

Issue

Part of #2095.

[Copilot]

Pull request overview

Fixes TOML integration generation (Gemini/Tabnine) so command descriptions are parsed with real YAML semantics (including | / > block scalars) and generated TOML prompt values exclude the source Markdown frontmatter.

Changes:

• Parse description from YAML frontmatter via yaml.safe_load to preserve block-scalar semantics.
• Split processed templates into frontmatter vs body so TOML prompt contains only the command body.
• Add regression tests covering block-scalar descriptions and prompt output excluding frontmatter.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/specify_cli/integrations/base.py	Updates TomlIntegration to YAML-parse description, split frontmatter/body, and render TOML strings more robustly.
tests/integrations/test_integration_base_toml.py	Adds regression coverage for YAML block scalar description parsing and for excluding frontmatter from TOML prompts.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

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