[MotherSphere]

Closes the remaining gaps against the Colony organisation rules (DEP-1, REL-10, DOC-3, DOC-5, DOC-10, FS-5, and the Raven side of FS-3).

What changes

Session state moves to the runtime directory (FS-5). session.pid and session.lock used to sit in ~/.local/share/Colony/Raven/environments/<env>/, where a record of a running session survived a reboot. They now live in $XDG_RUNTIME_DIR/raven/<env>/, beside the c mount point they describe, and go away with it.

• New paths::runtime_dir(name); mount_point is built on it.
• Environment::session_file() now returns a Result, because the runtime directory can be missing from the environment.
• Upgrade path: session() still reads the record a 0.5.0 anchor wrote in the data directory, so a launch right after the upgrade joins the running session instead of refusing to start. clear_session() removes both records. A reboot ends every such session, so this fallback can be dropped in a later release.
• The README Privacy table and the docs/internals/mount-stack.md tree describe the new location. The tree also gains the missing preferences.toml line.

Release profile (REL-10). [profile.release] uses lto = "thin", the organisation's profile. Fat LTO was only ever measured against the default profile, and start-up time did not change. docs/project/consolidation.md records the v0.5.0 fat-LTO raven-linux size (1 502 880 bytes) so the next release's size can be compared. The CI, gui.md and performance.md mentions of fat LTO are updated.

Dependencies (DEP-1). tokio 1.53.2 -> 1.53.3, and the lockfile is refreshed. ordered-float and uuid stay where they are, because their newer releases need a Rust newer than the 1.88 MSRV.

Preferences (FS-3, Raven side). Preferences::save creates its directory through colony_ui::paths::config_dir instead of its own create_dir_all.

README (DOC-3, DOC-5). The tagline now says who Raven is for. The intro is down to three sentences, and the rest of it moves into "Why Raven".

Release ledger (DOC-10). consolidation.md 3.3 covers v0.1.0 through v0.5.0. It says that v0.4.2 and later are signed by the shared sign-and-publish workflow with .sig, .meta and .meta.sig, and that v0.4.1 and earlier carry only .sig. The "Colony install verified" item stays open.

Not in this PR

FS-3 also asks for the hand-built path table in crates/raven/src/paths.rs to be replaced by colony_ui::paths. That is not possible yet: colony-ui depends on iced unconditionally, and the CLI must not pull in a GUI toolkit. The fix belongs upstream, as a GUI-free paths crate or an optional iced feature in colony-ui, and it needs a crates.io release. Until then, crates/raven-gui/tests/paths_parity.rs keeps the two tables identical.

Verification

• cargo fmt --all, and cargo clippy --workspace --all-targets --locked -- -D warnings is clean.
• cargo test --locked -p raven --lib: 117 passed. This includes two new session tests: the record sits beside the mount and not under data, and clearing a session removes the legacy record too. Afterwards, no test directories were left in the runtime directory.
• cargo test --locked -p raven-gui --bin raven-gui preferences: 3 passed.
• environment_recovery now also checks that a legacy record in the data directory still finds a live session. This integration test and session_anchor mount for real, so they run in CI.
• The v0.5.0 release assets were checked against the organisation key: every .sig and .meta.sig verifies, and every .meta matches its asset's version, name and sha256.