Rework the speaker: sans-I/O FSM, sharded table, RFC 7606, ADD-PATH

The work of the speaker-cleanup branch as one commit; the branch keeps
the step-by-step history.

Sessions
- The state machine is a pure function from events to actions, driven by
  one task per connection. Idle, Connect and Active belong to a dialer
  that keeps configured peers up with backoff.
- Capabilities are negotiated: address families, four-octet AS numbers
  with AS_TRANS and AS4_PATH, route refresh, ADD-PATH per family and
  direction.
- Collision detection per RFC 4271 section 6.8, by address and
  identifier.
- Connections are taken only from configured peers, a few per address.
- A panic in a session is contained and answered with a Cease; a core
  task that stops shuts the server down with a Cease to every peer.
- Writes that make no progress are given up (RFC 9687).

Codec
- Malformed UPDATEs are handled as RFC 7606 says: treat-as-withdraw,
  attribute discard, or session reset, with the NOTIFICATION to send.
- Address families are open types; any can be named and ignored.
- Prefixes are fixed-size values, normalised, with path identifiers.
- Lengths are filled in after writing; one definition of each type code.
- Property tests and fuzz targets for every decoder.

Routing table
- Adj-RIBs-In and Loc-RIB in one sharded table that sessions write to
  directly. Routes are sixteen bytes; attribute sets are interned in
  wire form. Best-path selection per RFC 4271 section 9.1.2.2 with
  deterministic MED.
- A journal per shard lets followers read changes at their own pace;
  one that falls behind is resynchronised.
- On a RIPE RIS dump of 148 peers and 39.3M routes: loaded in 2.0 s on
  12 cores, about 52 bytes a route.

Announcing
- Originated routes come from the configuration. Each session has its
  own exporter with an Adj-RIB-Out, so a slow peer delays only itself.
- Routes to a peer in our own AS have an empty path and a LOCAL_PREF.

Operations
- HTTP status page, JSON API, event stream and Prometheus metrics.
- Benchmarks on synthetic and real tables.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

@@ -1,8 +1,8 @@
 # BGP
 
-The `bgp` crate is an implementation of the Border Gateway Protocol, which is used to exchange routing and control plane information between Autonomous Systms.
+The `bgp` crate is an implementation of the Border Gateway Protocol, which is used to exchange routing and control plane information between Autonomous Systems.
 
-The aim of this project is to provide a modern, high performance, secure and programatic and customizable software package that can be useful to network operators, researchers, and people interested in Internet.
+The aim of this project is to provide a modern, high performance, secure, programmatic and customizable software package that can be useful to network operators, researchers, and people interested in Internet.
 
 ## Current status.
 
@@ -20,8 +20,38 @@ We aim for the 1.0 release to be functional and stable to operate peering sessio
     - ✅ Capabilities from RFC4271
   - ✅ Update message
   - ☐ Notification message
-- ☐ Implement scaffolding required to start and configure a server
-- ☐ Implement connection logic to establish sessions with peers
+- ✅ Implement scaffolding required to start and configure a server
+- ✅ Implement connection logic to establish sessions with peers (passive and active)
+- ✅ Routes originated from the configuration, with communities, announced to all peers
+- ✅ Read-only HTTP API, status page and Prometheus metrics
 - ☐ Implement an efficient data structure for storing prefixes (e.g. Poptrie)
 - ☐ Filtering for peer RIB in / out
-- ☐ Main / auxillary RIBs for exchanging routes between peers
+- ☐ Main / auxiliary RIBs for exchanging routes between peers
+
+## Development
+
+CI runs these three on every push, and fails on any warning:
+
+```
+cargo fmt --all -- --check
+cargo clippy --workspace --all-targets -- -D warnings
+cargo test --workspace
+```
+
+Lints are configured once, under `[workspace.lints]` in the root `Cargo.toml`.
+`unsafe` code is forbidden throughout.
+
+`cargo test` includes property tests: generated messages must survive being
+written and read back, and no input, however damaged, may make a parser
+panic. They take about a second; for a longer hunt:
+
+```
+PROPTEST_CASES=1000000 cargo test --release -p bgp-packet --test properties
+```
+
+Coverage-guided fuzz targets for the same parsers are in `fuzz/`; see
+`fuzz/README.md`. CI runs each of them for a minute.
+
+## License
+
+Apache License 2.0; see `LICENSE`.