feat(store): add tines-store persistent append-only LogStore

Add the host-side std `tines-store` crate implementing the `tines_core::Store`
trait over a durable, append-only single-file log so a robot's memory survives
reboot.

- Log format: length-prefixed `[u32 LE][postcard]` records (Obs/Trim/Meta).
- On load the index is rebuilt by replaying the log, then every age is
  rebased to load time: elapsed time since the last persisted clock marker is
  folded into `age_ms` and `stored_at` reset to load `now`, so ages continue
  instead of freezing across a reboot.
- Persisted state: released-id set, `next_seq`, and a clock marker in a `Meta`
  record; dedupe to the oldest Obs and let the last event per id win so a
  re-inserted id survives a trim.
- Implements `next_seq` and `flush`; `trim` writes Trim records best-effort.
- Registered as a workspace member; std-only, `#![forbid(unsafe_code)]`.
- Adds persistence tests (append durability, rebase-on-load, released/seq
  persistence). Full gate (fmt, clippy, docs, tests, no_std thumb build) is green.

tines-store/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "tines-store"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+description = "Persistent append-only LogStore backend for tines: memory survives reboot with rebased ages and persisted release/sequence state."
+authors.workspace = true
+repository.workspace = true
+readme.workspace = true
+documentation = "https://docs.rs/tines-store"
+keywords = ["robotics", "gossip", "delay-tolerant", "store", "persistent"]
+categories = ["science::robotics"]
+
+[dependencies]
+tines-core = { path = "../tines-core", version = "0.3.0" }
+postcard = { version = "1", features = ["use-std"] }
+serde = { version = "1", features = ["derive"] }