fix: support http(s) connection strings and sqld namespace URLs - #7

Summary

Three gaps made a sqld namespace URL (http://192.0.2.10:8080/dev/example/) unusable from Tabularis (all found during manual testing against a real self-hosted sqld):

1. Scheme not declared. .tabularium declared connection_uri: true but its connection_uri_schemes only listed turso, wss, ws and file. The host resolves a pasted connection string's protocol against that registry, so http:///https:// URIs were rejected as an unsupported driver before the plugin ever saw them — even though resolve_backend/normalize_remote_url already handled those schemes.
2. Decomposed params dropped the path. When the host sends host/port/database instead of the verbatim URI, the database value was ignored on the remote branch, so the plugin built http://host:8080 and posted to /v2/pipeline instead of the namespaced URL.
3. Path-based namespaces never selected the namespace. sqld resolves the namespace from the x-namespace header, not the URL path — 0.24.x serves /dev/<ns>/v2/pipeline but still takes the namespace from the Host header (the first octet of an IP literal), producing a 404 Namespace ... doesn't exist. The plugin now derives the namespace from the URL path (dev/example → example) and sends it as x-namespace.

• .tabularium: declare http and https; mention the sqld namespace form in connection_string_example
• src/client.rs: keep a multi-segment database value as a path prefix on the bare-host branch; Turso names contain no /, so plain names stay pathless
• src/hrana.rs: namespace_from_url_path + x-namespace header; plain hosts (Turso) send no header
• Regression tests: scheme/path preservation, connection_uri resolution, decomposed host/port/database (with/without trailing slash), plain-name no-path guard, namespace derivation/absence
• README + CHANGELOG (release 1.0.1), version bump in Cargo.toml and .tabularium

Closes #6

Test plan

• just test — 98 tests pass
• just lint — clippy -D warnings clean
• End-to-end against a local listener on port 8080:
  • {"connection_uri":"http://localhost:8080/dev/example/"} → captured POST /dev/example/v2/pipeline
  • {"host":"127.0.0.1","port":8080,"database":"dev/example/","ssl_mode":"disable"} → captured POST /dev/example/v2/pipeline
• Against a real self-hosted sqld 0.24.33 with the params the host sent: test_connection succeeds and metadata queries return real data; raw HTTP probes confirmed /dev/<ns>/v2/pipeline + x-namespace: <ns> → 200, while the same request without the header → 404.

Release

Merging this unblocks git tag v1.0.1, which triggers the release workflow. Run just dev-install + restart Tabularis to reload the manifest locally.