docs: add source link to GTM skills for directory visibility

[beingsmit]

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• I have read and followed the Guidance for submissions involving paid services.
• My contribution adds a new instruction, prompt, agent, skill, or workflow file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, skill, or workflow with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.
• I am targeting the staged branch for this pull request.

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Description

Adds a one-line source link under each GTM skill title. The skills.sh directory doesn't render frontmatter metadata, so the author/source info merged in #1100 isn't visible there. This adds it as body content so it shows up across all skill directories.

No content changes — just one blockquote line per skill.

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Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New plugin.
• New skill file.
• New agentic workflow.
• Update to existing instruction, prompt, agent, plugin, skill, or workflow.
• Other (please specify):

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Additional Notes

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

[github-actions]

🔍 Skill Validator Results

12 resource(s) checked | ✅ All checks passed

Full output

Found 11 skill(s)
[gtm-0-to-1-launch] 📊 gtm-0-to-1-launch: 2,924 BPE tokens [chars/4: 3,224] (standard ~), 15 sections, 2 code blocks
[gtm-0-to-1-launch]    ⚠  Skill is 2,924 BPE tokens (chars/4 estimate: 3,224) — approaching "comprehensive" range where gains diminish.
[gtm-ai-gtm] 📊 gtm-ai-gtm: 4,983 BPE tokens [chars/4: 5,339] (standard ~), 18 sections, 4 code blocks
�[31m❌ [gtm-ai-gtm] SKILL.md body is 563 lines — maximum is 500. Move detailed reference material to separate files.�[0m
[gtm-ai-gtm]    ⚠  Skill is 4,983 BPE tokens (chars/4 estimate: 5,339) — approaching "comprehensive" range where gains diminish.
[gtm-board-and-investor-communication] 📊 gtm-board-and-investor-communication: 4,363 BPE tokens [chars/4: 4,695] (standard ~), 17 sections, 2 code blocks
[gtm-board-and-investor-communication]    ⚠  Skill is 4,363 BPE tokens (chars/4 estimate: 4,695) — approaching "comprehensive" range where gains diminish.
[gtm-developer-ecosystem] 📊 gtm-developer-ecosystem: 2,116 BPE tokens [chars/4: 2,349] (detailed ✓), 15 sections, 2 code blocks
[gtm-enterprise-account-planning] 📊 gtm-enterprise-account-planning: 3,670 BPE tokens [chars/4: 3,950] (standard ~), 16 sections, 3 code blocks
[gtm-enterprise-account-planning]    ⚠  Skill is 3,670 BPE tokens (chars/4 estimate: 3,950) — approaching "comprehensive" range where gains diminish.
[gtm-enterprise-onboarding] 📊 gtm-enterprise-onboarding: 3,423 BPE tokens [chars/4: 3,613] (standard ~), 15 sections, 3 code blocks
[gtm-enterprise-onboarding]    ⚠  Skill is 3,423 BPE tokens (chars/4 estimate: 3,613) — approaching "comprehensive" range where gains diminish.
[gtm-operating-cadence] 📊 gtm-operating-cadence: 3,843 BPE tokens [chars/4: 4,042] (standard ~), 16 sections, 4 code blocks
[gtm-operating-cadence]    ⚠  Skill is 3,843 BPE tokens (chars/4 estimate: 4,042) — approaching "comprehensive" range where gains diminish.
[gtm-partnership-architecture] 📊 gtm-partnership-architecture: 3,558 BPE tokens [chars/4: 3,995] (standard ~), 17 sections, 4 code blocks
[gtm-partnership-architecture]    ⚠  Skill is 3,558 BPE tokens (chars/4 estimate: 3,995) — approaching "comprehensive" range where gains diminish.
[gtm-positioning-strategy] 📊 gtm-positioning-strategy: 3,234 BPE tokens [chars/4: 3,583] (standard ~), 16 sections, 3 code blocks
[gtm-positioning-strategy]    ⚠  Skill is 3,234 BPE tokens (chars/4 estimate: 3,583) — approaching "comprehensive" range where gains diminish.
[gtm-product-led-growth] 📊 gtm-product-led-growth: 3,093 BPE tokens [chars/4: 3,166] (standard ~), 16 sections, 3 code blocks
[gtm-product-led-growth]    ⚠  Skill is 3,093 BPE tokens (chars/4 estimate: 3,166) — approaching "comprehensive" range where gains diminish.
[gtm-technical-product-pricing] 📊 gtm-technical-product-pricing: 3,036 BPE tokens [chars/4: 3,258] (standard ~), 13 sections, 4 code blocks
[gtm-technical-product-pricing]    ⚠  Skill is 3,036 BPE tokens (chars/4 estimate: 3,258) — approaching "comprehensive" range where gains diminish.
{Ansi.Red}Skill spec conformance failures — fix the errors above.{Ansi.Reset}

Note: Errors were found. These are currently reported as warnings and do not block merge. Please review and address when possible.

[aaronpowell]

This is already in the frontmatter of the skills and adding them to the skills body adds unneeded weight into the context window.