Add ORDS pre-authenticated requests and sessionless transaction skills

[Fm0007]

Summary

This PR adds two new ORDS skills covering pre-authenticated requests (PAR) and sessionless transactions. It documents the current ORDS workflows, operational constraints, best practices, and common mistakes for both features, and updates the repository metadata so the advertised skill count matches the actual number of skills in the project.

What changed

• Added a new ORDS pre-authenticated requests skill covering:

  • prerequisites for ORDS_PAR.DEFINE_FOR_HANDLER
  • PAR creation and revoke flows
  • token, alias, and URI handling
  • URI parameter substitution requirements
  • security handling for PAR URLs as bearer secrets
  • operational notes for handler/module lifecycle
  • best practices for PAR duration and short-lived access
  • common mistakes around handler matching, token recovery, long durations, and revocation timing

• Added a new ORDS sessionless transactions skill covering:

  • the sessionless transaction workflow
  • transaction start, continue, commit, and rollback patterns
  • GTRID handling and request choreography
  • lifecycle, timeout, and safety guidance
  • common implementation mistakes and operational notes

• Updated the top-level skill metadata and index files to reflect the current total of 150 skills.

• Normalized inconsistent advertised totals across the repo.

Validation

• Reviewed both new ORDS skills for structure, consistency, and alignment with the rest of skills/ords.
• Re-checked the PAR guidance against current Oracle documentation and incorporated review feedback on duration, lifecycle, and revocation behavior.
• Validated the generated output against a live ORDS environment and used the results to correct the documentation where needed.
• Confirmed the repository skill count now matches the actual markdown skill files in skills/ after adding the two new ORDS skills.
• Verified the published totals are now consistent across:
  • AGENTS.md
  • SKILL.md
  • SKILLS.md

Notes

• This is a skills/documentation change only.
• No application code or runtime behavior was changed.

[krisrice]

Superseded by #25, which ports the absorbed ORDS PAR and sessionless transaction skills into the restructured skills/db/... layout for merge.