Get Started: programmatic path is broken end-to-end (SDK examples, cargo miden build, 404)

[melnikga]

While following the Get Started guide as a first-time user, I ran into a few issues on the programmatic path, the SDK
examples and building the first contract. Grouping the docs-side fixes here.

Full report: 0xMiden/feedback#149.

Docs fixes:

• 404 on the first link. The "Installation" card on /builder/get-started links
  to ./setup/installation, which resolves to /builder/setup/installation (404)
  on a cold load. Link directly to /builder/get-started/setup/installation.

• Notes & Transactions examples don't compile. mint.rs / consume.rs /
  send.rs import miden_protocol, which the scaffolded project doesn't depend
  on. (Template fix tracked separately in project-template; docs should either
  import from miden_client or note the dependency.)

• mint.rs fails at runtime on a transaction kernel assertion
  (error code: 16269270600290497661) with no readable message. Example needs
  updating against the 0.15.3 kernel.

• Read Storage example fails at runtime. read-count.rs hardcodes a counter
  account ID (0x224a96d294e10d006aef3d4f1b0876) that no longer parses
  ("0 is not a known account ID version"). Needs a valid live address.

• Wrong build command. The Create card says miden build, which doesn't
  exist (it proxies to midenc and errors). It should be cargo miden build.

• Manifest drift. The miden-project.toml shown on the Create card doesn't
  match what miden new generates: missing [package.metadata.miden]
  supported-types, and the increment-note namespace is increment-note in docs
  vs miden-increment-note generated (the #[note] macro expects the prefixed
  form).

• First-build heads-up (nit). The first cargo run of an SDK example pulls a
  nightly toolchain and builds ~400 crates (~4 min). One line warning would help.

Pages: get-started, cli-basics, accounts, notes, read-storage, create

[melnikga]

@BrianSeong99 , tagging you for visibility, and please assign this one to me