[7] Add initialize check to all contract functions

[EmeditWeb]

Problem

Public functions that read from persistent storage will panic with a VM trap if invoked before initialize() has been called. There is no is_initialized() guard, so any deploy-without-init race condition produces opaque failures rather than a clear NotInitialized error.

Context

The API frontend retries on transient errors. A panic on uninitialized state looks transient — but it isn't. Wrapping every public read with a typed init check lets the API surface a clear "contract not initialized" message and stop retrying.

Before Starting

Read these context files first:

• context/architecture-context.md
• context/code-standards.md
• context/progress-tracker.md
• contracts/*/src/lib.rs

What To Build

1. Add pub fn is_initialized(env: &Env) -> bool helper in each contract's lib.rs that checks env.storage().instance().has(&StorageKey::Admin).
2. At the top of every public function (mutating or read-only) that touches persistent storage, add: if !Self::is_initialized(&env) { return Err(ContractError::NotInitialized); }.
3. Exclude initialize() itself and any pure helper that doesn't read storage.
4. Add ContractError::NotInitialized = 1 variant in errors.rs if missing.
5. Write one regression test per contract that calls a getter before initialize and asserts NotInitialized.
6. Document the convention in code-standards.md.

Files To Touch

• All 5 contracts/*/src/lib.rs
• All 5 contracts/*/src/errors.rs
• All 5 contracts/*/src/tests.rs
• context/code-standards.md

Acceptance Criteria

• Every public function that reads storage starts with an is_initialized check
• ContractError::NotInitialized exists in all 5 error enums
• 5 regression tests pass
• No existing tests fail
• code-standards.md documents the convention

Mandatory Checks Before PR

• cargo build passes with zero errors
• cargo test — all 93 existing tests still pass
• require_auth() is FIRST line of every mutating function
• extend_ttl() called after EVERY persistent storage write
• New unit tests written for every new function
• context/progress-tracker.md updated

[Iwayemi-Kehinde]

I would like to work on this issue as I have reviewed the scope, I should have a PR Ready in 50 minutes.