refactor(workspace): rutster-signaling-sip → rutster-trunk; edition 2024; repo URL = git.adlee.work

ADR-0007 lands in code:
- Rename crates/rutster-signaling-sip → crates/rutster-trunk. The crate was
  a stub anyway (lib.rs with a doc-comment + crate_compiles() test); the
  rename locks the new boundary shape — the future rented-transport
  ingress (CPaaS media-leg fork / out-of-tree SBC glue, **no SIP stack**)
  lands here at spearhead step 5.
- rutster-trunk/src/lib.rs doc-comment now describes the ADR-0007 split:
  CPaaS media-leg adapter as primary, out-of-tree SBC for on-prem
  graduation. Cross-refs ADR-0007 + ADR-0008 (FOB vs. green zone: trunk
  is green zone; SIP lives outside the trust boundary).
- rutster-spend/src/lib.rs doc-comment updated to quote ADR-0007's
  'rutster mediates both the provider call-control API and the brain tap'
  framing — the spend gate sits in that boundary, structurally preventing
  a runaway brain from exceeding spend/pacing. Pulling spend out into a
  service re-introduces the 3-vendor structural hole.

Cargo bumps:
- edition = '2024' (slice-1's pinned Rust 1.85 + edition-2024 floor
  already requires this; rutster-media's let-else pattern in
  OpusDecoder::decode · Slice-2's let-else in AcceptOffer's Uuid
  parse_str · all rely on edition 2024's stabilized let-chains / let-else).
- repository = 'https://git.adlee.work/alee/rutster' (the self-hosted
  Gitea remote — matches 'git remote -v' origin). The github.com/anomalyco
  URL was stale from the pre-pivot copy.
- Cargo.lock regenerated by cargo for the rename.

No behavioral code changes — the trunk crate's body is still the stub
crate_compiles() test. FOB membership (per ADR-0008) is unchanged:
rutster-trunk will be FOB-internal at step 5 because it's the media-leg
ingress (hot path); spend-spend stays FOB because spend is
security-constitutive.

Cargo.toml

@@ -8,7 +8,7 @@ members = [
     "crates/rutster",
     "crates/rutster-call-model",
     "crates/rutster-media",
-    "crates/rutster-signaling-sip",
+    "crates/rutster-trunk",
     "crates/rutster-tap",
     "crates/rutster-tap-echo",
     "crates/rutster-spend",
@@ -16,8 +16,8 @@ members = [
 
 [workspace.package]
 license = "GPL-3.0-or-later"
-edition = "2021"
-repository = "https://github.com/anomalyco/rutster"
+edition = "2024"
+repository = "https://git.adlee.work/alee/rutster"
 
 # Pinned versions for all member crates. References are `foo.workspace = true`
 # in the member manifest. Keeps the dep tree unified (§2.1).