feat: initial repo setup (Phase 0 scaffolding)

- AGENTS.md: repo conventions adapted from alkcall/alksocks (store
  posture, multi-hash requirement, no-iroh-wire rule; no fuzz gate yet)
- Cargo.toml + src/lib.rs: bare lean lib skeleton (tokio async, thiserror)
- docs/research/phase-0.md: Phase 0 draft — vision, prior art (iroh-blobs
  store, gix-odb, alknet appfile probe, alkcall), OQ register, POC plan
- .gitignore, LICENSE-APACHE/MIT
- Re-pointed stale alknet/alkcall references in .opencode/agents/ and
  docs/sdd_process.md

Verification: cargo build/test, cargo clippy --all-targets -- -D
warnings, cargo fmt --check, cargo doc --no-deps — all pass

Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "alkblobs"
+version = "0.1.0"
+edition = "2021"
+rust-version = "1.88"
+license = "MIT OR Apache-2.0"
+description = "Content-addressed blob storage: multi-hash put/get/verify store with pluggable backends, transport- and protocol-agnostic"
+repository = "https://git.alk.dev/alkdev/alkblobs"
+keywords = ["blobs", "content-addressed", "storage", "gix", "bao"]
+categories = ["asynchronous", "filesystem", "database"]
+exclude = [".opencode/", "AGENTS.md", "docs/reviews/", "docs/research/", "docs/plans/", "tasks/", "docs/sdd_process.md"]
+
+[workspace]
+members = ["."]
+exclude = []
+
+[lib]
+name = "alkblobs"
+
+[dependencies]
+tokio = { version = "1", default-features = false, features = ["rt", "sync", "io-util", "macros"] }
+thiserror = "2"
+parking_lot = "0.12"