refactor: Reimplement display formats with askama templates

[adamspofford-dfinity]

Rich response display formats are currently implemented with a lot of ad-hoc printf style formatting. This PR replaces it with a proper template system. Askama was chosen because it is checked at compile time, so it will not increase the required test coverage.

[Copilot]

🟡 Changes recommended

An invalid Askama match arm blocks compilation, and several templates omit or misrepresent response data.

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Pull request overview

Replaces ad-hoc response formatting with compile-time Askama templates across ledger, governance, SNS, GTC, and ckBTC responses.

Changes:

• Adds shared formatting filters and response templates.
• Consolidates ICP and ICRC-1 ledger formatting.
• Adds Askama configuration and updates dependencies/MSRV.

File summaries

File	Description
Cargo.toml	Adds Askama and required IC dependency.
Cargo.lock	Locks new dependencies.
askama.toml	Configures template discovery and whitespace.
build.rs	Tracks template changes.
src/lib/mod.rs	Routes ledger responses through the consolidated formatter.
src/lib/format/mod.rs	Adds shared Askama filters.
src/lib/format/ledger.rs	Implements unified ledger rendering.
src/lib/format/icp_ledger.rs	Removes legacy ICP formatting.
src/lib/format/icrc1.rs	Removes legacy ICRC-1 formatting.
src/lib/format/ckbtc.rs	Migrates ckBTC responses to templates.
src/lib/format/gtc.rs	Templates claimed-neuron output.
src/lib/format/nns_governance.rs	Migrates NNS governance formatting.
src/lib/format/sns_governance.rs	Migrates SNS governance formatting.
src/lib/format/sns_root.rs	Templates SNS canister summaries.
src/lib/format/sns_swap.rs	Templates SNS swap responses.
src/lib/format/sns_wasm.rs	Templates deployed-SNS listings.
src/lib/format/templates/claim_neurons.txt	Defines claimed-neuron output.
src/lib/format/templates/ledger/transfer.txt	Defines successful transfer output.
src/lib/format/templates/ledger/transfer_err.txt	Defines ICP transfer errors.
src/lib/format/templates/ledger/icrc1_transfer_err.txt	Defines ICRC-1 transfer errors.
src/lib/format/templates/ledger/balance.txt	Defines ledger balance output.
src/lib/format/templates/ckbtc/update_balance.txt	Defines update-balance results.
src/lib/format/templates/ckbtc/update_balance_err.txt	Defines update-balance errors.
src/lib/format/templates/ckbtc/retrieve_btc.txt	Defines retrieval-start output.
src/lib/format/templates/ckbtc/retrieve_btc_status.txt	Defines retrieval statuses.
src/lib/format/templates/ckbtc/retrieve_btc_err.txt	Defines retrieval errors.
src/lib/format/templates/nns/proposal_info.txt	Defines NNS proposal details.
src/lib/format/templates/nns/neuron_ids.txt	Defines neuron-ID lists.
src/lib/format/templates/nns/min_neuron_info.txt	Defines compact neuron details.
src/lib/format/templates/nns/manage_neuron.txt	Defines manage-neuron results.
src/lib/format/templates/nns/list_neurons.txt	Defines neuron-list layout.
src/lib/format/templates/nns/full_neuron_info.txt	Defines full neuron details.
src/lib/format/templates/nns/claim_or_refresh_neuron_from_account.txt	Defines staking confirmation.
src/lib/format/templates/sns/refund.txt	Defines refund results.
src/lib/format/templates/sns/refresh_buyer_tokens.txt	Defines participation balances.
src/lib/format/templates/sns/new_sale_ticket.txt	Defines sale-ticket results.
src/lib/format/templates/sns/manage_neuron.txt	Defines SNS neuron results.
src/lib/format/templates/sns/list_snses.txt	Defines deployed-SNS output.
src/lib/format/templates/sns/get_buyer_state.txt	Defines buyer participation output.
src/lib/format/templates/sns/canisters_summary.txt	Defines SNS summary layout.
src/lib/format/templates/sns/canister_summary.txt	Defines individual canister details.

Review details

Suppressed comments (4)

src/lib/format/templates/nns/proposal_info.txt:215

• MakeProposal (c) is not valid Askama match-arm syntax; tuple payloads require with (...). This prevents the template derive from compiling.
  src/lib/format/templates/nns/proposal_info.txt:36
• A proposal that sets only wasm_memory_threshold is treated as non-empty by no_canister_settings, but this macro renders no value for it. Such a proposal therefore displays only the update heading and hides the actual change.
  src/lib/format/templates/nns/proposal_info.txt:235
• An Account may be present without an owner. This branch then calls icrc1_helper, whose account.owner.unwrap() panics; the previous formatter emitted unknown account for this valid missing-field case.
  src/lib/format/templates/sns/canister_summary.txt:15
• memory_allocation is measured in bytes, not percent. The current output presents a byte quantity as a percentage, while compute_allocation is the percentage-valued setting.

• Files reviewed: 40/41 changed files
• Comments generated: 4
• Review effort level: Balanced

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[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to f7118d7.

Security Overview

• 🔎 Scanned files: 42 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/ad75df36-1e5d-46c8-bb94-503b66f5bca2?scanId=acc9a830-37f8-47b5-9c84-0e1accfcbb8d&codeScanTypes=PrScan&tab=issues

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