Continue Watching and richer home rails on mobile and TV #38

Part of #52 (Post-v1 upgrade track). Post-v1, not scheduled — do not start before the owning v1 workstream ships unless the epic reprioritizes it.

Outcome

Continue Watching and richer media-first home sections on mobile and TV, per the TV feature spec home contract (three rows: Continue Watching, Recent Files, Pinned Folders) — deferred out of v1 parity by the kickoff plan.

Scope

• Server-synced progress semantics (>0% and <95% in-progress, >95% completed), pinned folders (max 10), recent files
• TV home evolves from the four-item parity menu to the rail-based home; mobile gets equivalent sections

Acceptance criteria

• DoD: verify green; captures of the new home on phone + TV emulator attached