fix: update puma for security advisories (#14670)

Updates Puma to the patched 7.2 line so bundle-audit no longer reports
the high-severity Puma advisories affecting the current lockfile.

Fixes: CVE-2026-47736, CVE-2026-47737
Closes: N/A

## Why

The refreshed ruby-advisory-db flagged Puma 6.4.3 for two high-severity
PROXY Protocol v1 parser advisories. The advisory-recommended fixed
versions are the Puma 7.2 patch line or Puma 8, so this keeps the update
to the smaller fixed line.

## What changed

- Constrains Puma to `~> 7.2`, `>= 7.2.1`
- Updates the lockfile from Puma 6.4.3 to 7.2.1
- Updates nio4r from 2.7.3 to 2.7.5 as the transitive Puma dependency

## Validation

- `bundle exec bundle-audit check` -> `No vulnerabilities found`
- `bundle exec rails runner 'puts "Rails #{Rails.version}; Puma
#{Puma::Const::PUMA_VERSION}; Rack #{Rack.release}"'` -> `Rails 7.1.5.2;
Puma 7.2.1; Rack 3.2.6`
- `bundle exec rails server -p 3051` booted Puma 7.2.1 successfully
- Smoke checked `/`, `/api`, unknown-route 404, and `/cable` WebSocket
upgrade

Gemfile

@@ -76,7 +76,7 @@ gem 'faraday_middleware-aws-sigv4'
 ##--- gems for server & infra configuration ---##
 gem 'dotenv-rails', '>= 3.0.0'
 gem 'foreman'
-gem 'puma'
+gem 'puma', '~> 7.2', '>= 7.2.1'
 gem 'vite_rails'
 # metrics on heroku
 gem 'barnes'

Gemfile.lock

@@ -593,7 +593,7 @@ GEM
       sidekiq
     newrelic_rpm (9.6.0)
       base64
-    nio4r (2.7.3)
+    nio4r (2.7.5)
     nokogiri (1.19.3)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
@@ -682,7 +682,7 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (7.0.5)
-    puma (6.4.3)
+    puma (7.2.1)
       nio4r (~> 2.0)
     pundit (2.3.0)
       activesupport (>= 3.0.0)
@@ -1132,7 +1132,7 @@ DEPENDENCIES
   pgvector
   procore-sift
   pry-rails
-  puma
+  puma (~> 7.2, >= 7.2.1)
   pundit
   rack-attack (>= 6.7.0)
   rack-cors (= 2.0.0)