docs(user-stories): add master CV onboarding stories (GAP-25)

[warnes]

Summary

Adds user stories and a gap entry for the documented but unspecified workflow of creating Master_CV_Data.json from scratch using external source materials. This addresses the onboarding gap previously noted in specstory history reviews: "There is no story for creating master CV from scratch for a first-time user."

New file

tasks/user-story-master-cv-onboarding.md

Twelve stories (US-O1–US-O12) across three persona layers:

Applicant / first-time user:

• US-O1 — Guided detection and path selection when no master CV exists
• US-O2 — Import from LinkedIn data export (ZIP with CSV files)
• US-O3 — Import from existing resume or CV document (PDF/DOCX via LLM extraction)
• US-O4 — Import publications from BibTeX file, Google Scholar URL, or pasted citation text
• US-O5 — Import projects and skills from a public GitHub profile
• US-O6 — Merge multiple sources into a unified master CV with conflict resolution
• US-O7 — Manual entry fallback via a guided multi-step form wizard
• US-O8 — Review and confirm all imported data before any write to disk

UI/UX expert:

• US-O9 — Evaluate onboarding source selection and import flow clarity
• US-O10 — Evaluate import error and gap handling (partial success, confidence signals, LLM latency)

Master CV curator:

• US-O11 — Post-import completeness check (section-by-section readiness summary)
• US-O12 — Conflict resolution when merging overlapping data from multiple sources

Updated files

File	Change
tasks/user-story-first-time-user.md	Add US-F4 — precondition detection and guided onboarding entry point
tasks/gaps.md	Add GAP-25 — Master CV Onboarding (HIGH severity, OPEN)
tasks/workflow-review-expanded-personas.md	Register new story file in the story-file index

Relationship to existing stories / gaps

• Complements US-A10 (update path) and GAP-01 (NL update + document ingestion) — these are distinct. US-A10 assumes master data exists; this PR covers the path to get there.
• Extends US-F1–F3 (first-time user orientation) with the master CV creation precondition.
• Extends US-M4 (publication curation) with an initial import path.
• The GitHub and Google Scholar paths are new — not mentioned in any prior story or spec.

Testing / review checklist

• Story IDs (US-O1–US-O12, US-F4, GAP-25) do not collide with existing IDs
• All stories follow the established format (persona, related gap, steps, acceptance criteria, failure modes)
• GAP-25 is consistent with the existing gap severity scale and description pattern
• workflow-review-expanded-personas.md story file list is complete