fix(fuse,core): key conflict detection on revision id, stop transient-name seals (B69, B70)

B69 — spurious `(sync-conflict)` copies came from `(mtime, size)` being used as a
revision identity. The server re-stamps a sealed revision with its own commit
time, so the drain diverted a write into a conflict copy of its own base; and
`plan_file` classified a no-baseline (local, remote) pair as `Conflict`, forking
every pre-existing file on first reconcile.

- `Baseline` carries `revision_id` (from the SDK's new `active_revision_id`),
  captured at write-open and preserved across supersede/rebaseline.
  `revision_changed` trusts the id and only falls back to `(mtime, size)` for
  old sidecars.
- Planner gains `FilePlan::AdoptBaseline`: equal-size no-baseline pairs are
  recorded, not conflicted. Divergent sizes stay a real conflict.
- New `sweep.rs` (`pdfs-conflict-sweep`, 5-min cadence) removes conflict copies
  proven identical by size + `content_sha1` and surfaces divergent ones once as
  an `ActivityKind::Conflict` entry. Never removes what it cannot prove.

B70 — browsers downloading into an on-demand mount had their in-flight temps
sealed as canonical revisions, exiling the finished file to a conflict copy.
`syncignore::is_transient_name` now recognises download/scratch temps, and the
on-demand `release`/`rename` paths hold them (`set_create_hold`) instead of
sealing until the name is finalized.

Workspace deps bumped to proton-sdk/proton-drive-rs 0.2.2 (registry, no patch).

Live validation against a real account still pending for both.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V8P42asymU158CPnhjRwri

Cargo.toml

@@ -10,8 +10,8 @@ authors = ["Nils Pukropp <contact@narl.io>"]
 rust-version = "1.96"
 
 [workspace.dependencies]
-proton-sdk = { version = "0.1" }
-proton-drive-rs = { version = "0.1" }
+proton-sdk = { version = "0.2.2" }
+proton-drive-rs = { version = "0.2.2" }
 
 # Internal crates.
 pdfs-core = { path = "crates/pdfs-core" }